To reset the GuruPlug, there is a good tutorial at plugcomputer.org: Reflashing images on the GuruPlug

If you did not destroy the whole u-boot (if you plug your GuruPlug in, you can see U-Boot starting and it at least runs until it shows "Hit any key to stop autoboot:"), you can start the tutorial from "Burning Kernel and Rootfs".

 

There were a few things that I struggled with. Therefore, this tutorial should be considered as extension to the tutorial on plugcomputer.org. Especially setting up tftp and getting the right files was tricky. I hope the screenshots also help to verify that you are on the right track.

Things which are needed are:

 

All the commands mentioned in the tutorial and here are executed on the Marvell-prompt. Right after u-boot started, press any key to get into the Marvell-prompt. Minicom will show something like this:

minicom_marvellprompt

 

Configure the network and burn the kernel image

minicom_burnkernel_uimage

 

Burn the root file system (rootfs) and set environment variables

Getting the rootfs per tftp is not visible in the picture. The command is:

>> tftp 0x6400000 rootfs.ubi.img

It will take quite a while to download. Also erasing and writing the NAND will take some time. Since writing the NAND does not show the progress, just wait until the OK-message shows up.

minicom_burnrootfs

Type

>> reset

to reset the GuruPlug. Go into the Marvell prompt again if you want to update U-Boot. Otherwise, just let it run and watch the boot process.

 

Update U-Boot

This step is optional, but it should not bother if you do it.

minicom_updateuboot

Type

>> reset

to reset the GuruPlug. Just let it run (do not go into the Marvell prompt) and watch the boot process.

 

Note:

Here is good information on how to get the most recent DENX U-Boot version